I have answered that question from you before. Why do you say they were "first"? In what sense were they first, when you consider that the original followers of Jesus were jews? Why is their opinion on scripture any more weighty than the far greater positive attestations through history of the Christian viewpoint?
To answer your question, the simple answer is that if they are correct, Christianity is wrong and all those who have literally given their lives for it have been fools.
Now answer my question - what if they are wrong and the Bible is correct, as I believe with all my heart?